Though, light bulbs in Mazda headlight in cars with 2.3 motor type might work wrong. With this base type must be P14.5s and cap of lamp is H1. Work of headlamp in every Mazda 6 is quite effective and appropriate. The recommendation of Mazda is to install only 55 W capacity lamps. In production of 2006 model year cars with engine code L3C1 the brand used high technology lamps. The best decision is to purchase for Mazda 6 2.0 efficient up-to-date bulbs of reliable producers. Especially lamps for 6 with plus capacity and 12 V voltage may be broken soon.
The obvious thing is that other cap than H1 won’t suit Mazda’s headlight module in 2003 model year. Nevertheless, you might buy more efficient than 55 W lamps, but the voltage stays strictly at 12 V. Installing P14.5s lamp by yourself can be hard for 2007 6 owners. To install new lamp in 6 with motor 2.0 relieve bulb holder at the backside of headlight.
There is no chance to install in 2003 Mazda any other type than H1 light bulb with P14.5s base. Observe all recommendations and your 2008 Mazda 6 will serve with no problems. Show caution in installing new bulbs in 6 with motor volume 2.2. Remember that any lamp is 12 V of voltage, power level on the pack is 55 W only.